posed of shale and limestone. Much of the range is protected by national and provincial parks, several of which collectively comprise a World Heritage Site. Geography The Canadian Rockies are the easternmost part of the Canadian Cordillera, the collective name for the mountains of Western Canada. They form part of the American Cordillera, an essentially continuous sequence of mountain ranges that runs all the way from Alaska to the very tip of South America. The Cordillera, in turn, is the eastern part of the Pacific Ring of Fire that runs all the way around the Pacific Ocean. View of Lake Louise in Alberta The Canadian Rockies are bounded on the east by the Canadian Prairies, on the west by the Rocky Mountain Trench, and on the north by the Liard River. Contrary to popular misconception, the Rockies do not extend north into Yukon or Alaska, or west into central British Columbia. North of the Liard River, the Mackenzie Mountains, which are a distinct mountain range, form a portion of the border between the Yukon and the Northwest Territories. The mountain ranges to the west of the Rocky Mountain Trench in southern British Columbia are called the Columbia Mountains, and are not considered to be part of the Rockies by Canadian geologi